Modern computers and related processing systems typically include a processor and some form of memory. The processor is generally responsible for performing the various computational tasks of the computer while the memory stores data that is used in and generated by the computational tasks. The architectural division of processing by the processor and data storage by the memory has proven successful for nearly the entire history of such systems.
For example, a typical general-purpose computer usually includes a central processing unit (CPU) and a main memory that communicate with one another over one or more communication channels (e.g., data, command and address buses). Typically, the CPU provides facilities to perform various arithmetic and logical operations, to provide operational sequencing, and to otherwise control aspects of the general-purpose computer. For example, virtually all CPUs provide functions or operations for reading data from memory, writing data to memory and executing programs comprising a set of instructions that utilizes the data to perform a predefined task. In addition, CPUs may handle input/output (I/O) allowing communication with peripherals as well as subsystems outside of the general-purpose computer. CPUs may even provide graphics processing to handle generating and updating a graphical display unit (e.g. a monitor), in some examples.
In contrast, the main memory of modern computers, which can include one or more of static random access memory (SRAM), dynamic random access memory (DRAM), read-only memory (ROM), programmable ROM (PROM), flash memory and a variety of other memory types, typically provides a relatively narrow set of capabilities. Principal among these capabilities is storing computer programs and data that are executed and used by the CPU. Among other limited capabilities that may be found in or that are often associated with the main memory of modern computers are certain memory management functions. For example, DRAM memory subsystems of main memory may possess circuitry for automatic refresh of data stored therein.
However, the historical architectural division of processing in the processor and storage in memory does present certain problems that are becoming more and more evident as time goes on. In particular, the conventional architectural division that centralizes all processing in the CPU while relegating the main memory to providing storage can and does present problems, especially as the memory is shared or used concurrently by one or both of multiple processes (e.g., threads) and multiple processors. Such concurrent processing systems, whether multi-threaded, multi-processor, or both, can present serious synchronization problems when considering shared and concurrently used main memory.
Certain examples have other features that are one of in addition to and in lieu of the features illustrated in the above-referenced figures. These and other features are detailed below with reference to the above-referenced figures.